WASHINGTON, DC, USA - Two remaining seeds at the Citi Open became one on Thursday, as Kazakhstan's Zarina Diyas upset No.5 seed Lesia Tsurenko for a spot in the quarterfinals, 6-4, 6-4.

In muggy conditions in which both players struggled physically, having both received a medical timeout over the course of the one hour and 52-minute clash, it was the unseeded Kazakh who made her opportunities count.

The World No.84 broke Tsurenko five times in the match, which included sprinting out to a 5-1 lead in the opening set, and ultimately broke in the last game of each set to seal her spot in the last eight. 

The result flipped the script of the pair's match from just three weeks ago, where Tsurenko beat Diyas in the first round of the Nature Valley International in Eastbourne on grass, 6-2, 6-2.

However, it was the lower-ranked of the two players who got off to the better start in Thursday's match, as she saved a break point in the first game and immediately set the tone by breaking her seeded foe to lead 2-0. 

An insurance break followed in the sixth game, but the Kazakh proved unable to serve out the first set on two occasions, before ultimately breaking Tsurenko for a third time to seal the set.

In the second, it was the No.5 seed who led 2-0 early, but Tsurenko dropped serve in the fourth game and lost three games in a row to lose her early advantage.

Both players had break point opportunities in the last five games from then on, but it was the Kazakh who converted successfully, finally winning the match on her first chance to do so.

More to come...